Arrival-Time Distributions as a Probe of the Preferred Foliation in Relativistic Bohmian Mechanics

Relativistic extensions of de Broglie-Bohm theory postulate a preferred foliation of spacetime, an additional structure essential for defining simultaneous configurations on Minkowski spacetime but conventionally believed to be empirically undetectable at quantum equilibrium. In this paper, we outline an experimental protocol for empirically detecting the preferred foliation, which is assumed to be flat for simplicity. Building on the arrival-time distributions for spin-1/2 particles predicted by Das and Dürr, we show that, in an Einstein-Podolsky-Rosen-Bohm-type experiment with spacelike-separated spin and arrival-time measurements, the observed arrival-time statistics will depend crucially on the temporal order of these measurements relative to the preferred foliation of spacetime. This dependence offers a potential experimental signature of the preferred foliation postulated by relativistic Bohmian models. Moreover, it implies the possibility of superluminal signaling.